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Magnetic properties of soils from sites with different geological and environmental settings 总被引：7，自引：0，他引：7
Hana Fialov Günter Maier Eduard Petrovský Ale&#x; Kapi
ka Tetyana Boyko Robert Scholger MAGPROX Team 《Journal of Applied Geophysics》2006,59(4):273-283
Measurements of magnetic susceptibility of soils, reflecting magnetic enhancement of topsoils due to atmospherically deposited magnetic particles of industrial origin, are used recently in studies dealing with outlining polluted areas, as well as with approximate determination of soil contamination with heavy metals. One of the natural limitations of this method is magnetic enhancement of soils caused by weathering magnetically rich parent rock material. In this study we compare magnetic properties of soils from regions with different geological and environmental settings. Four areas in the Czech Republic and Austria were investigated, representing both magnetically rich and poor geology, as well as point-like and diffuse pollution sources. Topsoil and subsoil samples were investigated and the effect of geology and pollution was examined. Magnetic data including mass and volume magnetic susceptibility, frequency-dependent susceptibility, and main magnetic characteristics such as coercivity (Hc and Hcr) and magnetization (Ms and Mrs) parameters are compared with heavy metal contents. The aim of the paper is to assess the applicability of soil magnetometry under different geological-environmental conditions in terms of magnetic discrimination of dominant lithogenic/anthropogenic contributions to soil magnetic signature. Our results suggest that lithology represents the primary effect on soil magnetic properties. However, in case of significant atmospheric deposition of anthropogenic particles, this contribution can be clearly recognized, independent of the type of pollution source (point-like or diffuse), and discriminated from the lithogenic one. Different soil types apparently play no role. Possible effects of climate were not investigated in this study. 相似文献
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A. K. Pavlov A. V. Blinov G. I. Vasil’ev M. A. Vdovina A. N. Konstantinov V. M. Ostryakov 《Astronomy Letters》2014,40(10):640-647
The production of the cosmogenic radionuclides 14C, 10Be, and 36Cl in the Earth’s atmosphere under the action of powerful impulsive proton and gamma-ray events (superpowerful solar flares and Galactic gamma-ray bursts) is considered. The possible “isotopic footprint” in natural archives (the concentrations of these isotopes in dated polar ice cores and annual tree rings) has been calculated by taking into account geophysical processes. The results obtained have been applied to analyzing the anomalous increase in the concentration of radiocarbon measured in tree rings dated 774–775 AD. Arguments for the fact that the most likely cause of this increase is the high-energy emission from a Galactic gamma-ray burst are adduced. 相似文献
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A. K. Pavlov A. V. Blinov G. I. Vasilyev M. A. Vdovina P. A. Volkov A. N. Konstantinov V. M. Ostryakov 《Astronomy Letters》2013,39(9):571-577
An explanation is offered for the impulsive increase in the concentration of cosmogenic radiocarbon in annual tree rings (Δ14C ～ 12‰) from AD ?775. A possible cause of such an increase could be the high-energy emission from a Galactic gamma-ray burst. It is shown that such an event should not lead to an increase in the total production of 10Be in the atmosphere, as distinct from the effect of cosmic-ray fluxes on the atmosphere. At the same time, the production of an appreciable amount of 36Cl, which can be detected in Greenland and Antarctica ice samples of the corresponding age, should be expected. This allows the effects caused by a gamma-ray burst and anomalously powerful proton events to be distinguished. 相似文献
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A. S. Ivleva V. N. Podkovyrov V. B. Ershova V. B. Khubanov A. K. Khudoley S. N. Sychev N. I. Vdovina A. V. Maslov 《Doklady Earth Sciences》2018,480(2):695-699
The results of LA–ICP–MS U–Pb analyses of detrital zircons from the Precambrian deposits of Luga–Ladoga monocline are discussed. The age spectra of the zircons separated from the Riphean to Upper Vendian sandstones from the Shotkusa-1 well demonstrate dominance of the Paleo- and Mesoproterozoic grains while the Archaean zircons are subordinate. The Riphean debris sources were local swells of the Northern Ladoga basement. The sequence interval presumably corresponding to the Vasilieostrov Formation (Upper Vendian) has yielded not only Paleo- and Mesoproterozoic zircon ages, but Neoproterozoic as well, implying a Timanide provenance: these zircons (527 ± 9 and 516 ± 13 Ma) allow deposition of a significant part of the Shotkusa-1 sequence at the very beginning of the Cambrian. 相似文献
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The numerical error associated with finite-difference simulation of wave propagation in discontinuous media consists of two
components. The first component is a higher-order error that leads to grid dispersion; it can be controlled by higher-order
methods. The second component results from misalignment between numerical grids and material interfaces. We provide an explicit
estimate of the interface misalignment error for the second order in time and space staggered finite-difference scheme applied
to the acoustic wave equation. Our analysis, confirmed by numerical experiments, demonstrates that the interface error results
in a first-order time shift proportional to the distance between the interface and computational grids. A 2D experiment shows
that the interface error cannot be suppressed by higher-order methods and indicates that our 1D analysis gives a good prediction
about the behavior of the numerical solution in higher dimensions.
相似文献
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